Description
Dwyer SERIES 641 AIR VELOCITY TRANSMITTER
High Accuracy, Field Selectable Ranges
The Series 641 Air Velocity Transmitter is the ideal instrument for monitoring air flow. This transmitter uses a heated mass flow sensor which allows for precise velocity measurements at various flow rates and temperatures. The 641’s 16 field selectable ranges provides it the versatility to be selected for several air flow applications. The optional LED produces a complete, low-cost solution for local indication of air flow.
Features:
- Ranges from 250 FPM (1.25 MPS) to 15,000 FPM (75 MPS)
- Optional bright LED display
- Easy push button set-up
- Compact housing
- 4 to 20 mA output
- Digital filter for signal damping
Applications:
- Exhaust stack flow monitoring
- Air control in drying processes
- HVAC air velocity measurements
- Fan supply and exhaust tracking
- Clean room fresh air supply
- Ensure proper lab hood exhaust flow rates
Specifications:
- Service: Clean air and compatible, non-combustible gases
- Accuracy: 3% FS Process gas: 32 to 122°F (0 to 50°C); 4% FS Process gas: -40 to 32°F & 122 to 212°F (-40 to 0°C & 50 to 100°C)
- Response Time: Flow: 1.5 s to 95% of final value (output filter set to min.)
- Temperature Limits: Process: -40 to 212°F (-40 to 100°C). Ambient: 32 to 140°F (0 to 60°C)
- Pressure Limit: 100 psi (6.89 bar) maximum
- Humidity Limit: Non-condensing
- Power Requirements: 12 to 35 VDC, 10 to 16 VAC. 1.5 A rating required on supply due to initial power surge drawn by transmitter
- Output Signal: 4 to 20 mA, isolated 24 V source, 3 or 4-wire connection
- Output Filter: Selectable 0.5-15 s
- Loop Resistance: 600 Ω max
- Current Consumption: 300 mA max
- Electrical Connections: Screw terminal
- Process Connections: 1/2″ male NPT
- Enclosure Rating: Designed to meet NEMA 4X (IP66) for non LED models only
- Mounting Orientation: Unit not position sensitive. Probe must be aligned with airflow
- Weight:12.6 oz (357.2 g)
- Agency Approvals: CE
- OPTIONAL DISPLAY VERSION: Display:4-1/2 digit 1/2″ red LED
- Resolution: 1 FPM, 0.01 MPS (10 FPM @ 10,000 and 15,000 FPM ranges)
- Weight:13.3 oz (377 g).
Models:
| 641-12 | Air velocity transmitter, 12″ (304.8 mm) probe length. |
| 641-12-LED | Air velocity transmitter, 12″ (304.8 mm) probe length, with LED display. |
| 641-18 | Air velocity transmitter, 18″ (457.2 mm) probe length. |
| 641-18-LED | Air velocity transmitter, 18″ (457.2 mm) probe length, with LED display. |
| 641-24 | Air velocity transmitter, 24″ (609.6 mm) probe length. |
| 641-24-LED | Air velocity transmitter, 24″ (609.6 mm) probe length, with LED display. |
| 641-30 | Air velocity transmitter, 30″ (762 mm) probe length. |
| 641-30-LED | Air velocity transmitter, 30″ (762 mm) probe length, with LED display. |
| 641-36 | Air velocity transmitter, 36″ (914 mm) probe length. |
| 641-36-LED | Air velocity transmitter, 36″ (914 mm) probe length, with LED display. |
| 641-6 | Air velocity transmitter, 6″ (152.4 mm) probe length. |
| 641-6-LED | Air velocity transmitter, 6″ (152.4 mm) probe length, with LED display. |
